Maharshi Valmiki is considered as the Adi Kavi. He was the first person to compose poetry. He was the inventor of the meter called ‘Shloka’. He was the writer of the first ever epic – Ramayana. The Sanskrit word Kavi is generally translated to the English word ‘Poet’. But ‘Kavi’ is a non-translatable word. It means many things including - wise, enlightened, gifted, skilful, knowing, thinker, bard, seer, prophet, and a man of knowledge, understanding and intelligence.
Valmiki is also called a Maha-Rishi. Rishi is generally translated as a ‘Seer’, he who sees, he who is a visionary. Again, Rishi is a non-translatable word. It means not only seer, but also an ascetic, a composer of Vedic hymns, a ray of light, a sage, an inspired poet and an enlightened being. Valmiki is described as Maha-Rishi, a Great Rishi! It is such an enlightened one who writes about the journey of Rama. In his work, Valmiki suggests three names for the epic –
Narada Muni tells Valmiki Rishi about the doings of Rama, at the Valmiki Ashram on the banks of Tamsa river. Kangra painting, National Museum, New Delhi.
काव्यं रामायणं कृत्स्न्नं सीतायाश्चरितं महत् |
पौलस्त्यवधमित्येवं चकार चरितव्रतः || १-४-७ ||
He says this work can be titled as – Ramayana (The Journey of Rama), SeetaCharita (The Life and Deeds of Seeta) or Paulatsya-Vadh (The assassination of Ravana, a descendant of Pulatsya Rishi) . This only highlights that for the writer Valmiki, Seeta was as important as Rama. In Valmiki’s Ramayana, Seeta did not play a supporting role, but she played the lead role along with Rama. It is thus the birth place of the slogan “जय सियाराम”, Victory to Sita-Rama!
When one reads Valmiki Ramayana, one is amazed not only by the subjects it covers, but also by the minute details that are provided. Ramayana speaks of the Geography of Bharata, of its Rivers and mountains, of her Seasons, of the flora of Bharata, of the History of Ikshavaku dynasty, about the Social Institutions, about War Strategies, about Dharma, about Spiritual practices, about human behaviour, psychology and even about mathematics. Do note that this is not an all inclusive list of the subjects covered by Valmiki’s Ramayana. I will try to expand on some of the above points.
Valmiki describes the Geography of the area from the kingdom of Kekay (today’s Northern Pakistan) to the kingdom of Videha (today’s Nepal). Also from Hastinapur (on the banks of Ganga) to Lanka in the South. Through Sugreeva he describes the geography of areas that are farther off and beyond those mentioned above. He describes the mountain ranges like the Himalayas, the Vindhya, the Malaya Parvat, Rishyamukh Parvat, the Mandadri and others. He describes the rivers like the Vitatsa (Jhelum), Shatudru (Sutlej), Sarasvati, Yamuna, Ganga, Sharayu, Gomati, Mandakini, Godavari, Tungabhadra and many others. He not only mentions those rivers but speaks of their depth, their waters and their speed. He describes the birds on the banks of these rivers. He also describes the plants and trees that the trio, Rama-Lakshmana-Seeta encounter in their journey. He describes the nuances of the seasons. His descriptions of Vasant, Sharad and Varsha are so detailed that while reading those one can also smell the fragrances that he speaks of!
He is an excellent reader of human character and behaviour. While reading the feelings of his characters tears well up in the eyes of the reader. The brotherly love of the four brothers, father’s love of Dasharatha, Dasharatha’s pining for Rama, the guilt that Bharata feels due to his mother’s deed, Rama’s heart of lion, Rama’s pangs of separation from Seeta, Seeta’s composition of steel, the shades of jealousy Kausalya feels towards Kaikayi, the anger Bibhishana feels when insulted by Ravana, the loyalty of Hanuman ... the list is simply unending.
He tells how the numbers were counted from 100 to 1072. When a messenger of Ravana describes the army of Sugreeva, he tells -
“This Sugreeva, the king of monkeys, having great strength and valour, always surrounded by a colossal army, is approaching you to make war. He is accompanied by the valiant Vibhishana and the ministers, as also a hundred thousand crores of Shankas, a thousand Mahashankus, a hundred Vrindas, a thousand mahavrindas, a hundred padmas, a thousand Mahapadmas, a hundred kharves, samudras and Mahaughas of the same number, and a crore of Mahaughas whole army as such is identical of an ocean. “ 
Valmiki speaks extensively of the Dharma, that is the duties and responsibilities, of a King, of a warrior, of a minister, of mother, father, brother and son etc. Here is one example where Valmiki speaks about the duties of a King. When Bharata goes to see Rama at Chitrakoot, Rama inquires upon him if he was following the duties of a king. He asks –
“Dear Bharata, are you taking care of the subjects of Ayodhya? Are those who live by farming and cattle rearing taken care of by you? Are you ensuring protection to the women folk of Ayodhya? I hope you are also taking care of the animals and the trees that stand at the cross roads in our kingdom. I hope you are holding in high esteem the teachers, elders and the doctors. Pray, tell me you are treating our mothers and teachers and ministers with respect. I hope you are honouring the Brahmins, but not those who are materialistic. I hope you have appointed valiant, incorruptible and learned ministers because for a king, the source of victory comes from a counsel by ministers, who are well-versed in political sciences. I hope you do not take excess of sleep and do wake up early. I do hope that you use the night hours to contemplate on your actions. Do make sure that you take up welfare projects that have minimum cost but maximum benefit, and do not delay them in anyway. I hope you are giving salaries to the army and your employees without delay. I hope you are keeping a watch on the happenings within the state and beyond through a good network of spies. O mighty Prince! A wise and a learned king, who rules the Earth with righteousness ascends to heaven after discarding the body." – Valmiki Ramayana, Ayodhya Kanda, Sarga 100. 
Such detailed are the instructions about Dharma in Ramayana, that the reader will become influenced by it. India has seen a great many kings who were influenced by Ramayana and had Rama as their ideal king. Not just in India, but wherever Ramayana was read, the kings there wanted to be like Rama. The shining example being the old capital of Thailand that was named Ayutthya (Ayodhya) and her kings still call themselves ‘Rama’. An inscription of King Yashovarma of Cambodia reads, “My capital is like that of Rama’s Ayodhya.” While another 10th century inscription of Rajendravarma reads “... like SriRama this king took care of his subjects like a father.”
As a poet Valmiki is the king of similes. He gives not one but many similes to describe one thing. Example when Sage Vishvamitra comes to visit King Dasharatha, the King says he is delighted to receive the Sage. He says, “Your arrival brings me delight that can be likened to the delight of a mortal attaining ambrosia, or the coming of rains in dry land, or a barren father begetting a son through his deserving wife, or regaining of long lost treasures, and the gladness at a great happening! Oh, great saint, welcome to you.”
Valmiki generously uses elements of nature as similes. Example to say, “Rama and Lakshamana are arriving.” he writes, “Rama whose complexion is like that of a blue lotus, and Lakshamana whose complexion is like that of the moonlight, came together.”  His description creates a live picture for the eyes of the mind, and gives goosebumps to the skin.
Valmiki describes himself as – the 10th son of Prachetas. Further he says, in my life I have never hurt anyone through my deeds, my words or even in my thoughts!
प्रचेतसोsहं दशम: पुत्रो राघवनन्दन।
मनसा कर्मणा वाचा भूतपूर्वं न किलविशम || 7.93.17 ||
It is this tender-hearted, pure soled Valmiki who we see throughout the pages of Ramayana. Once the sage was at the banks of river Tamsa, happily watching a pair of krounch birds (Curlews), who were flying about together merrily. Suddenly a hunter shot the male bird with his arrow. Covered in blood, the bird fell to the ground in agony.
The female bird wailed at his plight. Her piteous utterances moved the Sage to utter a curse in form of a Shloka -
मां निषाद प्रतिष्ठां त्वमगमः शाश्वतीः समाः।
यत्क्रौंचमिथुनादेकम् अवधीः काममोहितम्॥ 1.2.15 ||
Oh violent hunter (निषाद), for killing one bird, when it was infatuated by passion, you shall not (मां) achieve fame for everlasting years to come!
This verse when read in a different way means – Oh Vishnu (at whose feet Lakshmi seats herself मां निषाद), for killing one bird (Ravana) who was infatuated by lust, you shall achieve fame for everlasting years to come! 
For a long time, Valmiki was unable to forget the sad mourning of the female bird. In that state of melancholy, Brahma advised him to write the Ramayana. Valmiki wrote the Ramayana in 24,000 verses. It is divided in 7 sections called Kanda. Each Kanda having many chapters called Sarga. Brahma said -
यावत् स्थास्यन्ति गिरयः सरितः च महीतले |
तावत् रामायण कथा लोकेषु प्रचरिष्यति || 1.2.36 ||
As long as the rivers flow on this Earth, as long as the mountains remain immovable, until then O Sage, your Ramayana will remain popular amongst the people!
It is this Ramayana of Valmiki that has inspired many a kings and rulers to be righteous. It has inspired many brothers to be like Rama, Lakshmana and Bharata. It has taught one to be a friend like Sugreeva and Vibhishana. It has taught not only how the family relations should be, but also how an ideal society should be. Valmiki’s Ramayana is considered as a Upajivya Kavya, a work that has provided livelihood to many for generations together. Story tellers, writers, actors, artists, architects, singers, dancers, poets and so many have made a living by retelling Ramayana through various mediums. Not just India, the world owes its humanness to Valmiki, had he not written the Itihas of Rama, we would have never known about it.
1. Spoken Sanskrit Dictionary
2. Valmiki Ramayana
3. Similes in Ramayana – Dr. Madhusudan Phatak
4. English Translation of Valmiki Ramayana at valmikiramayana.net